Bridge management system developed for the local governments in Japan

There are over one-hundred-and-forty-thousand road bridges with a span of 15 meters or longer in Japan, and about 35% of them were built within the high growth period of 1960's and 1970's and the aging of the road bridges will be one of the problems for the road administrators in the near future. Since more than 75% of the total number of bridges are managed by the local governments, authors have challenged to develop a Bridge Management System (BMS) which can be used by many local governments in common. One of the main purposes for the local governments to implement the BMS is to estimate the Life-Cycle Cost (LCC) to maintain the road bridges in safe and proper condition and reduce it as low as possible. In order to reduce the LCC, it is necessary to examine the deterioration process of individual bridge component, which is referred to as "Micro Management", and to establish an overall maintenance plan for all the bridges, which is referred to as "Macro Management". Since the process of establishing a long-term maintenance plan for all the bridges is very complicated, it is usual to treat Micro Management and Macro Managements differently. The authors have developed a new Bridge Management System, which treats both Micro and Macro Management in a closely related manner by utilizing the concept of "Maintenance Scenario". The deterioration prediction is one of the key issues in the development of BMS. Since the deterioration of the bridge component is heavily dependent on the environmental condition, it is usual to establish a deterioration curve based on the statistical analysis of the inspection data. But this method cannot be applied to most of the local governments in Japan, because most of them do not have enough inspection data to execute the statistical analysis. Therefore, authors have introduced a new method of establishing deterioration curves applicable to local government which have insufficient inspection data. The developed BMS has been applied to the actual bridge management in Aomori Prefectural Government very successfully, and authors intend to spread it among the local governments in Japan.